The present invention relates to chairs, and in particular, to an adjustment mechanism for controlling the height and the tilt of a seat for a chair, as well as the angle of the chair backrest relative to the seat.
It is well known in the art to incorporate mechanisms into a chair to permit the tilting of the chair back and/or seat in order to enhance the comfort of a user. In order to control the positioning of the seat and backrest, complicated mechanisms are often required. These mechanisms are actuated by a plurality of handles, buttons, levers and the like in order to control the various movements of the seat. The plurality of handles not only detract from the aesthetic properties of the chair, but also render adjustment of the seat and backrest difficult for a user who is unfamiliar with the operation and function of each actuator.
Further, prior art adjustment mechanisms tend to be complicated in that they require many parts. For example, in Miotto, U.S. Pat. No. 5,348,371, a chair is provided which incorporates a mechanical device to effectuate the synchronous movement of the seat and backrest. In order to selectively lock the seat in a user selected stationary position, a plurality of friction discs are provided. By rotation of a handle under the seat of the chair, the discs are compressed so as to prevent movement of the seat by friction. The large number of parts involved in this type of locking arrangement adds to the overall cost and complexity of the mechanism.
Therefore, it is a primary object and feature of the present invention to provide a chair control mechanism which is simple to operate and inexpensive to manufacture.
It is a further object and feature of the present invention to provide a chair control mechanism for a chair wherein a user may adjust the vertical height of the seat with one lever and the seat and backrest angle with another lever.
It is a further object and feature of the present invention to provide a chair control mechanism wherein the angle of the seat with respect to the supporting surface of the chair, and the angle of the backrest relative to the seat, may be easily manipulated and selectively locked into position with a single handle.
In accordance with the present invention, a device for adjusting the position of a seat of a chair is adapted for use with a pedestal including a central vertical column. The central column includes a gas piston assembly for varying the length thereof. An enclosure is connectable about an upper end of the central column. An actuator element is pivotably mounted to the enclosure and movable between a first actuating position wherein the actuator element actuates the gas piston assembly thereby allowing the length of the central column to be adjusted to a user selected length, and a second non-actuating position wherein the central column is maintained by the gas piston assembly at the user selected length. A handle extends from the enclosure and is pivotably movable between a first position wherein the handle urges the actuator element into the first, actuating position, and a second position. Means are provided for urging the actuator element toward the non-actuating position.
It is also contemplated to provide a plunger housing extending laterally from the enclosure and a plunger element slidably supported therein. The plunger element has a first end engaging the actuator element and a second end engaging the handle wherein movement of the handle between the first and second positions causes the plunger element to slide axially within the plunger housing. The handle is pivotably mounted to the plunger housing such that a first end of the handle extends into the plunger housing and a second end of the handle extends outwardly therefrom.
The device also includes a seat bracket interconnected to the seat and a link element pivotably mounted to the seat bracket and to the enclosure, for interconnecting the seat bracket to the enclosure. The link element allows for limited horizontal and vertical movement of the seat bracket with respect to the enclosure. An intermediate bracket is pivotably mounted to the enclosure and to the seat bracket at a location spaced from the link element, and pivotable movement of the seat bracket with respect to the enclosure results in a corresponding pivotable movement of the intermediate bracket with respect to the enclosure over a predetermined range. The intermediate bracket may be locked at a user selected position for selectively fixing the position of the seat bracket to the enclosure, and thereby the position at the seat relative to the pedestal. A back support member is connected to the intermediate bracket, such that movement of the intermediate bracket results in adjustment in the angular position of the back relative to the seat. In this manner, the angle of the back is adjusted synchronously with adjustment of the seat angle.
In accordance with another aspect of the invention, a seat adjustment mechanism is provided for controlling movement of a seat of a chair. The seat adjustment mechanism includes a bracket assembly operatively connected to the seat for allowing horizontal and vertical movement of the seat over a predetermined range. A locking element is provided for locking the seat at a user selected position within the predetermined range.
In accordance with yet another aspect of the invention, a device is provided for interconnecting a seat to a central support. The device includes an enclosure operatively connected to the support. A seat connection bracket is operatively connected to the seat and a link element interconnects the enclosure and the seat connection bracket. An intermediate bracket is pivotably mounted to the enclosure and to the seat connection bracket wherein a predetermined pivotable movement of the intermediate bracket with respect to the enclosure translates into a corresponding predetermined movement of the seat connection bracket with respect to the enclosure. A locking member is provided for maintaining the intermediate bracket in one of a plurality of predetermined positions with respect to the enclosure.
Various other features, objects and advantages of the invention will be made apparent from the following description taken together with the drawings.